Armature with sheet steel laminates and method for production thereof

ABSTRACT

An armature according to the prior art, which is comprised of sheet metal laminations and in which only a beginning region and an end region of the lamination bundle comprised of the sheet metal laminations are fastened to a rotor shaft by means of a press fit, has the disadvantage that sheet metal laminations between the beginning region and the end region shift in the presence of very high torques.  
     An armature ( 1 ) according to the invention is comprised of a number of modules ( 8, 9, 10 ), wherein each module ( 8, 9, 10 ) has a beginning region ( 12 ) and an end region ( 13 ) that are each fastened to the rotor shaft ( 3 ) so that even in the presence of very high torques, the holding force for the sheet metal laminations between the beginning region and end region is so great that they do not shift.

PRIOR ART

[0001] The invention is based on an armature and method for producing an armature as generically defined by the preamble to claim 1 and claim 5.

[0002] It is known to affix a lamination bundle, which is comprised of a number of sheet metal laminations, to a rotor shaft by means of pressing them onto the shaft in order to produce an armature for an electric machine. There is both positive and frictional engagement between each sheet metal lamination and the rotor shaft. Particularly with a large number of sheet metal laminations, i.e. a long lamination bundle, it is difficult to fasten this to the rotor shaft in one step without damaging sheet metal laminations and/or the rotor shaft. Frequently, so-called stepped rotor shafts are used, which are complex to produce and are more expensive.

[0003] It is also known to fasten a lamination bundle to rotor shaft by attaching only a beginning region and an end region, which are each comprised of at least one sheet metal lamination, to the rotor shaft by means of caulking. Particularly with long lamination bundles and high torques, there is the possibility of the sheet metal laminations between the beginning region and the end region shifting due to insufficient holding forces in the lamination bundle.

ADVANTAGES OF THE INVENTION

[0004] The armature according to the invention and the method according to the invention for producing an armature, with the characterizing features of claim 1 and claim 5, have the advantage over the prior art that sheet metal laminations are securely affixed to a rotor shaft in a simple manner.

[0005] Advantageous modifications and improvements of the armature and the method for producing an armature disclosed in claims 1 and 5 are possible by means of the measures and process steps taken in the dependent claims.

[0006] In order to produce an attachment between the sheet metal lamination and the rotor shaft, it is advantageous to fasten the sheet metal lamination to the rotor shaft by means of a plastic deformation of the sheet metal lamination.

[0007] One advantage for the armature is achieved in that the rotor shaft has a continuous outer diameter because such a rotor shaft is easy and inexpensive to produce.

[0008] It is advantageous if the sheet metal laminations have approximately the same inner diameter because this reduces the number of types of sheet metal laminations and eliminates confusion among different sheet metal laminations with regard to the sequence in which they are stacked.

DRAWINGS

[0009] An exemplary embodiment of the invention is shown in simplified fashion in the drawings and will be explained in detail in the subsequent description.

[0010]FIGS. 1a, b, and c show how an armature according to the invention is produced, which is comprised of a rotor shaft and modules, and

[0011]FIG. 2 shows an axial cross section through an armature according to the invention.

DESCRIPTION OF THE EXEMPLARY EMBODIMENT

[0012]FIG. 1a shows a rotor shaft 3 and a number of sheet metal laminations 5, which constitute components of an armature 1 according to the invention. An armature 1 of this kind is used for an electric machine, e.g. an electric motor or an electric generator.

[0013] A number of sheet metal laminations 5, which comprise a first module 8, are fastened to the rotor shaft 3. Each module has a beginning region 12, a middle region 14, and an end region 13.

[0014] The attachment can be produced in various ways, e.g. by pressing sheet metal laminations 5 with a round bore onto a notched or knurled rotor shaft 3. In this instance, the sheet metal laminations 5 have different inner diameters di. The sheet metal laminations 5 of the beginning region 12 and end region 13 have a smaller inner diameter di than the sheet metal laminations 5 of the middle region 14. The inner diameter di of the sheet metal laminations 5 in the beginning region 12 and end region 13 is designed so that an attachment of the sheet metal laminations 5 to the rotor shaft 3 is produced according to one of the methods mentioned above, exclusively in these regions 12, 13.

[0015] The middle region 14 is held by the frictional engagement acting in the axial direction between the beginning region 12 and end region 13.

[0016] In another type of attachment, a number of sheet metal laminations 5—all of the sheet metal laminations 5 having the same inner diameter di within the range of tolerance and constituting a module 8—are slid onto the rotor shaft 3, wherein the outer diameter d of the rotor shaft 3 and the inner diameter di of a through bore 18 of the sheet metal laminations 5 are selected so that no attachment is produced at first, i.e. there is a clearance fit. For example, the rotor shaft 3 has a continuous outer diameter d.

[0017] The first module 8—which is comprised for example of four sheet metal laminations 5—is then fastened to the rotor shaft 3 at a predetermined location on the rotor shaft 3. This occurs by virtue of the fact that an attachment is produced between at least one sheet metal lamination 5 and the rotor shaft 3, exclusively in the beginning region 12 and end region 13 of the first module 8.

[0018] This can once again occur in various ways, for example through plastic deformation of the rotor shaft 3 or plastic deformation of the sheet metal laminations 5 in the beginning region 12 and end region 13 (FIG. 1a), in which material of the respective sheet metal lamination 5 is slid onto the rotor shaft 3 and produces a caulked attachment to the rotor shaft 3, or through the insertion of wedges between the sheet metal lamination 5 and the rotor shaft 3 in the beginning region 12 and end region 13.

[0019] The plastic deformation of the rotor shaft 3 or of the beginning region 12 and end region 13 is produced by caulking tools 11, which are indicated by arrows in the drawings.

[0020] In the next step (FIG. 1b), a second module 9, which is likewise comprised of a number of sheet metal laminations 5, is slid with play onto the rotor shaft 3 and is brought into contact, for example, with the first module 8.

[0021] Then in the end region 13 of the second module 9, an attachment is once again produced between at least one sheet metal lamination 5 and the rotor shaft 3 by means of the caulking tool 11.

[0022] This step can also be repeated a number of times, as also shown in FIG. 1c, in which a third module 10 is also disposed on the rotor shaft 3 and is fastened in the end region 13.

[0023] The armature 1 according to the invention is made up of a number of modules 8, 9, 10 that comprise a lamination bundle 7 and are each attached separately to the rotor shaft 3. The modules 8, 9, 10 can also be attached to the rotor shaft 3 spaced a certain distance apart from one another.

[0024]FIG. 2 shows an axial cross section through an armature 1 according to the invention, according to FIG. 1c.

[0025] The armature 1 according to the invention is comprised, for example, of three modules 8, 9, 10. Each module 8, 9, 10 is comprised of the beginning region 12 and the end region 13, between which the middle region 14 is situated. The beginning region 12 is comprised of at least one sheet metal lamination 5, which is fastened to the rotor shaft 3.

[0026] The beginning region 12 and end region 13 of the modules 8, 9, 10 are each thus secured to the rotor shaft 3 by means of a fastening region 16—or a caulking region 16 if the attachment is produced through caulking—which beginning region 12 and end region 13 are each comprised of one (FIG. 2) or more sheet metal laminations 5. The middle region 14 is held by the frictional engagement acting in the axial direction between the beginning region 12 and end region 13. The sheet metal laminations 5 of the middle region 14 do not constitute a frictional engagement with the rotor shaft 3 that would be enough to secure the sheet metal laminations 5 to the rotor shaft 3 at high speeds.

[0027] The second module 9 likewise has a beginning region 12, a middle region 14, and an end region 13. The end region 13 of the first module 8 can also simultaneously constitute the beginning region 12 of the second module 9, even if this is only comprised of one sheet metal lamination 5.

[0028] Thus the end region 13 of the second module 9 simultaneously constitutes the beginning region 12 of the third module 10. Particularly in long lamination bundles, i.e. with a very large number of sheet metal laminations 5, this modular design is advantageous. Even in the presence of very high torques, which act on the sheet metal laminations in the middle region 14, no shifting of the sheet metal laminations 5 occurs in these regions 14.

[0029] The number of sheet metal laminations 5 for a module 8, 9, 10, and the position of the modules 8, 9, 10 in relation to one another can be freely selected.

[0030] Likewise, sheet metal laminations 5 can be rotated in order to reduce an imbalance. 

1. An armature for an electric machine, comprised of at least one rotor shaft and at least five sheet metal laminations, wherein at least three sheet metal laminations are fastened to the rotor shaft, characterized in that at least three sheet metal laminations (5) constitute a module (8, 9, 10), in that a number of modules (8, 9, 10) are disposed on the rotor shaft (3), in that each module (8, 9, 10) has a beginning region (12), a middle region (14), and an end region (13), and in that only the beginning region (12) and the end region (13) of the module (8, 9, 10) are fastened to the rotor shaft (3), while the middle region (14) has play in relation to the rotor shaft (3) on which it is disposed.
 2. The armature according to claim 1, characterized in that the attachment of the beginning region (12) and the end region (13) is produced through plastic deformation of at least one sheet metal lamination (5).
 3. The armature according to claim 1 or 2, characterized in that the sheet metal laminations (5) have approximately the same inner diameter (di).
 4. The armature according to claim 1, characterized in that the rotor shaft (3) has only one outer diameter (d).
 5. A method for producing an armature with a rotor shaft and sheet metal laminations disposed on the rotor shaft, characterized in that a number of sheet metal laminations (5) are combined to form a first module (8) and are slid with play onto the rotor shaft (3), in that the first module (8) is then fastened to the rotor shaft (3) only in a beginning region (12) and an end region (13), and in that at least one additional module (9, 10) is slid onto the rotor shaft (3) with play and in its end region (13), is separately fastened to the rotor shaft (3).
 6. The method for producing an armature according to claim 5, characterized in that the beginning region (12) and end region (13) are fastened to the rotor shaft (3) through plastic deformation by means of a caulking tool (11). 